A taxonomic review of the Amazonian rheophyte Schusterolejeunea Grolle (Lejeuneaceae: Cololejeuneinae), with two new combinations Author Sierra, Adriel M. Instituto Nacional de Pesquisas da Amazônia, Departamento de Biodiversidade, Avenida André Araújo, 2936, Aleixo, CEP 69060 - 001, Manaus, AM (Brazil) and Département de Biologie, Université Laval, Québec (QC), G 1 V 0 A 6 (Canada) and Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec (QC), G 1 V 0 A (Canada) adsierra 26 @ gmail. com (corresponding author) adsierra26@gmail.com Author Zartman, Charles E. Instituto Nacional de Pesquisas da Amazônia, Departamento de Biodiversidade, Avenida André Araújo, 2936, Aleixo, CEP 69060 - 001, Manaus, AM (Brazil) text Cryptogamie, Bryologie 2023 2023-04-12 20 4 107 122 http://dx.doi.org/10.11646/zootaxa.4878.3.2 journal article 250381 10.5252/cryptogamie-bryologie2023v44a4 23c643b8-8759-4bec-8e12-b8ac658108d9 1776-0992 7841602 Schusterolejeunea inundata var. fontinaloides (Spruce) A.M.Sierra & C.E.Zartman , comb. nov. ( Fig. 4 ) Lejeunea inundata var. fontinaloides Spruce, Transactions and Proceedings of the Botanical Society of Edinburgh 15: 278 ( Spruce 1884 ) . LECTOTYPE . — Brazil . Est. Amazonas , Paricatuba , leg. Spruce s.n. (lecto-, designated in Grolle 1980 , MANCH !; isolecto-, G ). SPECIMENS EXAMINED. — Brazil . Amazonas, along the Rio Cauaburi between the Rio Negro and the Cachoeira do Carangueijo, 0°15’00”S , 65°55’00”W , mostly rocky flood plain forest, 3.VII.1979 , Buck W.R. 2314 (INPA!, NY); Rio Negro, igarapé Foibara, vecinity of first cachoeira of the Igarapé Foibará of Rio Negro, 0°16’00”S , 66°35’00”W , Terra firme forest, 22.VII.1979 , Buck W.R. 2627 (INPA!, NY); Schuster R.M. 79-21-1135 (INPA!, NY); Santa Isabel do Rio Negro, Rio Cauaburi, 0°15’00”S , 65°55’00”W , Schuster 79-10-295 (INPA!, NY); Ilha Acarabu, at the mouth of the Rio Marié, 0°25’00”S , 66°25’00”W , Marshy forest, 4.VII.1979 , Schuster R.M. 79-11-302 (INPA!, NY); Manaus, Rio Negro, igapó forest in the island in front of the Praia da Lua, 3°01’56.5”S , 60°09’44.7”W , epiphyte on trunk in seasonal inundated forest (igapó), 25.XI.2017 , Sierra A.M. 4583 , 4582 , 4586 (INPA!, PMA!); São Gabriel da Cachoeira, Rio Negro, banco de areia frente da cidade de São Gabriel da Cachoeira, 0°08’29.2”S , 67°05’04.1”W , sobre rochas sazonalmente inundável, 14.XII.2017 , Sierra A.M. 4642 (INPA!); Rio Negro, 20 km descendo da cidade de São Gabriel da Cachoeira, Ilha Cariuari, 0°11’45.8”S , 67°00’10.9”W , floresta de igapó, 17.XII.2017 , Sierra A.M. 4713 , 4724 (INPA!, PMA!), 4714 , 4718 , 4720 (INPA!, SP!), 4719 (INPA!, SP!, PMA!), 4710 (INPA!); Rio Uaupés, Sitio São Paulo , 0°02’50.3”N , 68°29’05.7”W , epífita sobre ramas na margem do rio, 21.XII.2017 , Sierra A.M. 5055 , 5063 (INPA!, PMA!), 5056 , 5059 (INPA!, SP!, PMA!); São Gabriel da Cachoeira, Rio Negro, Ilha em frente a São Gabriel da Cachoeira, 0°07’49.0”S , 67°05’21.1”W , sobre pedra na ilha, 20.VII.1979 , Yano O. 2103 (INPA!, SP); Rio Negro, Temenduí, 0°22’00”S , 64°42’00”W , sobre rochas grandes submersas na água, 29.VI.1979 , Yano O. 1536 (INPA!, SP); Rio Negro, São Tomé, Margem do rio, 0°22’00”S , 64°10’00”W , 29.VI.1979 , Yano O. 1528 (INPA!, SP); Rio Negro, Ilha Acarabu, 0°40’00”S , 66°40’00”W , sobre raízes de plantas submersas na água, 4.VII.1979 , Yano O. 1640 (INPA!, SP); Rio Negro, NW de São Gabriel da Cachoeira, em tronco submerso na água, 21.VII.1979 , Yano O. 2139 (INPA!); Novo Airão, Parque Nacional Jaú, Carabinani river, 2°02’38”S , 61°33’28”W , rheophyte on sand along the Carabinani river, X.2007 , Zartman C.E. 7547 , 7544 (INPA!) . See Appendix 1. FIG. 4. — Schusterolejeunea inundata var. fontinaloides (Spruce) A.M.Sierra & C.E.Zartman , comb. nov. : A -C , gametophyte in ventral view, showing androecia and gynoecia branches; D , single leaf detail; E , F , lobule close-up; G , leaf insertion showing basal leaf cells; H , mid leaf cells.Micrography from Sierra A.M. 4582 . Scale bars: A-D, 400 μm; E, F, 100 μm; G, H, 50 μm. DISTRIBUTION. — Schusterolejeunea inundata var. fontinaloides (Spruce) A.M.Sierra & C.E.Zartman , comb. nov. is relatively common in the Brazilian Amazon. It is known from several localities in the state of Amazonas along the Rio Negro Basin (including the type locality), and in the Rio Pacaás Novos in Rondônia . HABITAT. — Schusterolejeunea inundata var. fontinaloides (Spruce) A.M.Sierra & C.E.Zartman , comb. nov. occurs in fast-flowing streams in black water seasonally flooded igapó forests in the Amazonas state , as well as white water várzea forests along Rio Pacaás Novos in Rondônia state ( Appendix 1 ). It grows attached to rocks, tree branches, roots, trunks, and leaf surfaces. DESCRIPTION Habit Plants small to medium in size, shoots up to 2 cm long and 1-2.5 mm wide, pale to dark green or yellow, creeping to loosely pendant, highly branched, with numerous gametangia, usually with fertile innovations. Branches Lejeunea - type . Stems Primary stems in cross-section with seven cortical and three medullary thick-walled cells, epidermis slightly enlarged, without hyalodermis; ventral merophytes two cells wide. Leaves Distant to continuous, patent, obliquely spreading, to suberect (45° with stem) insertions short composed of two ventral and 3-4 dorsal cells, ovate, (350) 600-1200 µm long, (160) 280- 570 µm wide, (1.5) 2-5 times as long as wide, apices rounded, plane, margins entire, dorsal margins arched, ventral lobe margins slightly to widely arched after the lobule keel. Cells with numerous chloroplasts, oil bodies finely granular, 2-4 per cell. Leaf lobe cells hexagonal, quadrate, or rectangular, thin-walled, trigones small, intermediate thickenings scarce, cuticles smooth. Basal laminal cells hexagonal to rectangular (16-50 ×9-24µm), mid laminal cells short, rectangular to quadrate, rarely hexagonal (10-30×10-25µ m), marginal cells mostly quadrate to short rectangular (10-23 (30) ×10-19 µm). Stylus unicellular. Lobules Small, usually well-developed, broadly expanded, arching obliquely upward or erect parallel to the stem, triangular or fin shaped, (170) 250-510 µm long, (80) 130-200 µm wide, covering less than 1/4 of the leaf lobes, with a narrow base, keels straight to arched, formed by 6-12 cells; apices rounded. Teeth inconspicuous, formed by two cells with a marginal hyaline terminal papilla at the lobule apex. Underleaves Small, narrower than the stem, 2-6 × longer than wide, (140-360 ×50-115µ m) narrowly bifid with erect lanceolate lobes composed of 3-13 cells long, lobes at base composed of 2-4 cells wide, sinus deeply V-shaped. Rhizoids brown or hyaline, up to 11-16 µm wide and thick-walled (3µm wide). Autoicous Androecia numerous, on short lateral branches at both sides of the stem. Spikes (420-1100 (1700) × 350-570 µm) with 2-4 (8) imbricate pairs of perigonial bracts; bracts ovate bilobed, and emarginate at the apices. Bracteoles arise as underleaves for each bract pair. Gynoecia on short lateral branches originating at the bases of vegetative leaves, 2-4 in a monochasial row with 1-3 innovations of the pycnolejeuneoid type , which is again fertile (except the outermost one). Female bracts (630-750 µm), short, obovate, bilobed, entire margins with emarginated or obtuse apices; lobules lingulate, with rounded apices. Bracteoles like the underleaves. Perianths obpyriform (580) 630- 720× 250-430µ m, with five distinct keels 2/3 of the perianth length, keel margin entire or crenulated by bulging cells, beak short 2-celled. COMMENTS This variety is easily distinguished by its ovate leaves which are 1.5-2.5× longer than wide, small lobules, covering less than half of the leaf lobe, usually triangular with the keel extending to 6-12 cells. Within an individual specimen, this taxon may show morphological variability among primary and secondary branches, as some secondary shoots may present small elliptical leaves with lingulate lobules. However, primary stem characters hold to the above description.